Developer roll

ABSTRACT

This invention relates to image developing apparatus and specifically a developer roll for use in combination with a color producing substrate. In accordance with this invention, a color is formed by the reaction of isolated chromogenic materials. A first chromogenic material is typically a color precusor of the electron donating type whereas the second chromogenic material is typically identified as a color developer and is generally of the electron accepting type. In this invention a developer roll bunishes the active coating on the color producing substrate to promote the reaction of the color forming ingredients. This developing action is accomplished without &#34;rupturing pressure&#34; or without the necessity for pressure rollers which define a pressure nip.

BACKGROUND OF THE INVENTION

The instant invention relates to image developing apparatus andspecifically a developer roll for use in combination with a colorproducing substrate. In accordance with this invention, a color isformed by the reaction of isolated chromogenic materials. A firstchromogenic material is typically a color precursor of the electrondonating type whereas the second chromogenic material is typicallyidentified as a color developer and is generally of the electronaccepting type. In this invention a developer roll burnishes the activecoating on the color producing substrate to promote the reaction of thecolor forming ingredients. This developing action is accomplishedwithout "rupturing pressure" or without the necessity for pressurerollers which define a pressure nip.

One type of substrate for which image developing apparatus such as thedeveloper roll of this invention is necessary is commonly referred to ascarbonless paper. Carbonless paper is a common, commercially used typeof pressure sensitve paper wherein during manufacture the backside ofthe paper substrate is coated with what is referred to as CB coating,the CB coating containing one or more color precursors generally incapsular form. At the same time the front side of the paper substrate iscoated during manufacture with what is referred to as a CF coating,which contains one or more color developers. Both the color precursorand the color developer remain in the coating compositions on therespective back and front surfaces of the paper in colorless form.

This is true until the CB and CF coatings are brought into contiguousrelationship and sufficient pressure, as by a typewriter or stylus, isapplied to rupture the capsules in the CB coating to release the colorprecursor. At this time the color precursor contacts the CF coating andreacts with the color developer therein to form a color. Generally, thiscolor is formed in a pattern of an image such as an alphanumericcharacter or the like. Thus the image from the top surface of the topsheet is transferred to the next sheet without the use of carbon paper.

A related product, and one for which the developer roll of thisinvention has special utility is referred to as self-contained paper.Very generally, self-contained paper refers to an image transfer systemwherein only one side of the paper needs to be coated and the onecoating contains both the color precursor, generally in encapsulatedform, and the color developer. Thus, when pressure is applied, again asby a typewriter, stylus or other writing instruments, the colorprecursor capsule is ruptured and the internal phase reacts with thesurrounding color developer to form an image. Both the carbonless papersystem and the self-contained carbonless paper system have been thesubject of a great deal of patent activity.

A second type of product which requires developer roll activity isdescribed as self-developing film for use with fully automaticphotographic cameras. Typical of these cameras and the film which isused in them is Polaroid Corporation's SX-70 and Pronto and EastmanKodak Company's EK-6 and EK-8 cameras. These cameras and the film usedtherein are designed to automatically produce finished, waste free colorprints with virtually no operator involved other than to compose thepicture, focus and then actuate the camera by depressing its cycle startbutton.

Once actuated, the order of camera operations begins with exposure of afilm unit. Afterwards, the exposed film unit is advanced from itsexposure location into engagement with a film processing subsystem orapparatus which initiates a diffusion transfer process in the film unitwhile transporting it to the exterior of the camera where it becomesaccessible to the photographer. After the diffusion transfer process isinitiated, it develops and forms a visible image in the film unit in awell-known manner.

Typically necessary in systems such as this are pressure rollers todiffuse the active ingredients. See for example, U.S. Pat. No. 2,435,717(1948) to Land; U.S. Pat. No. 2,495,113 (1950) to Gannon. Also describedin the prior art are pressure ebbs for "film pods", see for example,U.S. Pat. No. 2,659,825 (1953) to Land or along the same lines squeezingrollers such as demonstrated by U.S. Pat. No. 2,751,814 (1956) toLimberger. Other patents generally known to be pertinent to this conceptare U.S. Pat. No. 2,971,445 (1961) to Orlando; U.S. Pat. No. 3,134,313(1964) to Gold et al.; U.S. Pat. No. 3,249,434 (1966) to Land et al.;U.S. Pat. No. 3,615,132 (1971) to Turner; U.S. Pat. No. 4,017,879 (1977)to Lermann et al.; U.S. Pat. No. 4,200,382 (1980) to Friedman; and U.S.Pat. No. 4,256,392 (1981) to Stemme et al.

Another line of products which typically require developer rolls or thelike are described in previously mentioned U.S. Pat. No. 3,615,132 toTurner and assigned to the Xerox Corporation. These patents describewhat is referred to as the process of xerography, which is alsodisclosed for example in Carlson Pat. No. 2,297,691. In this process axerographic plate comprising a layer of photoconductive insulatingmaterial on a conductive backing is given a uniform electric charge overits surface and then exposed to the subject matter to be reproducedusually by conventional projection techniques. This exposure dischargesthe plate areas in accordance with the light intensity that reachesthem, and thereby creates an electrostatic latent image on or in thephotoconductive layer. Development of the latent image is effected withan electrostatically charged, finely divided material, such as anelectroscopic powder, which is brought into surface contact with thephotoconductive layer and is held thereon electrostatically in axerographic powder image pattern corresponding to the electrostaticlatent image. Thereafter, the developed xerographic powder image isusually transferred to a support surface, such as, a sheet of copy paperto which it may be fixed by any suitable means.

Since the disclosure in Carlson, many improvements have been inxerographic devices and techniques and, as a result, both manual andautomatic machines for carrying out xerographic reproduction processesare in wide commercial use.

While a variety of commercial processes involving a color development orcolor transfer system have been described above, they all suffer from acommon deficiency. In any of the systems wherein color development takesplace between co-reactive materials, it is common to use pressurerollers for purposes of developing the color. This is done when theco-reactant materials are maintained in isolation from one another. Byuse of the apparatus and method of this invention pressure rollers areno longer necessary for the development of colors between co-reactedmaterials. Rather than use a pressure nip to crush, squeeze, diffuse orotherwise physically distort coatings or substrates a more subtle forceis applied by means of the developer roll of this invention. Thedeveloper roll of this invention relies on a burnishing effect on theactive surface of the reactive coating and the optional application ofheat to develop, enhance and project developed colors. Commondisadvantages of the high pressure rollers common to the prior artsystems are that they require not only high pressure, but also precisionalignment in order to develop color without crimping or creasing thesheet.

Several terms need to be defined for purposes of this application. Theterm "rupturing pressure" should be understood to mean the pressurenecessary to crush microcapsules coated onto a paper substrate. Intypical carbonles paper embodiments wherein rupturing pressure isapplied by means of a typewriter or stytus-like instrument, in order toassure uniform capsule rupture a rupturing pressure of greater than 100kg/cm² is required.

The "force" necessary to release the internal phase of capsules shall beunderstood to mean the burnishing force, heat force or frictional forcedeveloped by use of the apparatus of this invention to rupture orrelease the contents of the microcapsules which have been coated ontothe substrate.

The term "image-wise exposing" shall be understood to mean that thereaction between the chromogenic material and the developer occuraccording to the exposure such that a positive or negative image isobtained. The image may be formed by a change in color or a differencein contrast.

SUMMARY OF THE INVENTION

Thus, a principle object of the present invention is to provide adeveloper roll which does not rely on pressure for the development ofcolor between co-reactive components.

Another object of the present invention is to provide an inexpensive andlightweight development system which is adaptable to use in smallphotocopiers; cameras, and other apparatus wherein convenience, size andweight are of paramount importance.

Still another object of the instant invention is a safe developmentapparatus which does not require pressure nips such as in the prior artwhich are known to be unsafe if not used properly.

A more specific object of the present invention is to provide adeveloper apparatus for use with self-contained photosensitive paperswhich does not rely on crushing or squeezing pressures as are typical ofprior art systems.

These and other objects of this invention are attained in the presentinvention in which its preferred embodiment relates to the use of aphotosensitive substrate which includes: a substrate, a chromogenicmaterial, a photosensitive composition, a coating containing achromogenic material and a photosensitive composition on one surface ofthe substrate, and a developer material which is capable of reactingwith the chromogenic material to form a visible image, wherein saidphotosensitive composition is encapsulated in a pressure rupturablecapsule as an internal phase. For more information concerning thisgeneral concept and specifics as to this imaging system reference ismade to commonly assigned copending patent applications Ser. Nos.320,643 and 302,356 both filed on Nov. 12, 1981, which disclosure isspecifically incorporated herein by reference.

Herein, the term "encapsulated" refers to both so-called dispersion oropen phase systems in which the internal phase containing thephotosensitive composition and optionally the chromogenic material aredispersed as droplets throughout a dispersing medium and also to systemsin which the capsule is formed with a discrete capsule or wall, thelater encapsulation typically being in the form of microcapsules.

"Pressure rupturable capsules" are, accordingly, considered to exist ineither of these "encapsulated" systems. When generically referring tothese materials the phrase "isolated" will sometimes be used. This termshould be understood to mean that one or the other of the co-reactivematerials must be isolated from the other in order to prevent prematurecolor development.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a developer roll showing one embodiment of this invention;

FIG. 1A is a cross-sectional view of the developer roll of FIG. 1.

FIG. 2 is a developer roll showing a second embodiment of this inventionwith flexible bristles;

FIG. 2A is a cross-sectional view taken along the line 2A--2A in FIG. 2and showing the flexible bristle embodiment of the developer roll ofthis invention;

FIG. 3 is a schematic of a positive working diazo process utilizing thedeveloper roll of this invention;

FIG. 4 is a schematic of a positive working photocopying apparatus usingthe developer roll of this invention;

FIG. 5, is a schematic illustration in cross-sectional of aself-contained imaging sheet having use in combination with thedeveloper roll of this invention;

FIG. 6 is a schematic illustration of exposure and development of theimaging sheet of FIG. 5; and

FIG. 7 is a schematic illustration of the developed sheet of FIG. 6.

DETAILED DESCRIPTION OF THE INVENTION

For the purposes of promoting and understanding of the principles ofthis invention, reference will now be made to the embodimentsillustrated in the drawings and specific claims will be used todescribed the same. It will nevertheless be understood that nolimitation of the scope of the invention is thereby intended, suchalterations and further modifications in the illustrated device, andsuch further application of the principles of the invention asillustrated therein contemplated as would normally occur to one skilledin the art to which the invention relates.

FIG. 1 illustrates one embodiment of the developer roll of thisinvention. In FIG. 1 the developer roll 10 is shown as comprising amandrel 11 and an outer fibrous surface 12. Outer fibrous surface 12 iscomposed of interwoven fibers of natural or synthetic material. A commonexample of a developer roll such as this is the commonly availablereplaceable roll used for purposes of painting. These rollers as well asthe rollers which are useful in the developer roll invention of thisapplication typically consist of matted fibers or other flexiblematerial. This description of the "outer fibrous surface" is notintended to be limiting but rather as merely illustrative of the variousembodiments contemplated. The variety of paper and chemicals to bedeveloped may well dictate the specific outer fibrous surfaces to beused. A felt outer surface is also considered a preferred embodimenttogether with the flexible bristles and paint roller surface as alreadydescribed.

FIG. 1A shows a cross-sectional area of developer roll 10 of FIG. 1, butshows in more detail fibrous outer surface 12. Mandrel 11 is intended toprovide the rotational basis for the developer roll 10. Mandrel 11 mayconsist of one or more parts which may be variously sized depending uponspeeds and equipment which are used in the developing process.

A second embodiment of the developer roll of this invention isillustrated by FIGS. 2 and 2A. In FIG. 2 the developer roll 10 includesa mandrel 11 as well as a fibrous outer surface 12. However, in FIG. 2the fibrous outer surface 12 consists of a plurality of flexiblebristles 13.

FIG. 2A shows in cross-section the embodiment of FIG. 2. Illustratedmore clearly are the mandrel 11, fibrous outer surface 12 and flexiblebristles 13. It should be understood that the embodiments illustrated byFIGS. 1 and 2 are meant to be merely exemplary of a large variety ofsurface materials which can be used in the developmental process of thisinvention.

Although the developer roll 10 of this invention is intended for usewith a variety of reactive substrates and in combination with a varietyof imaging apparatuses, two examples are provided for purposes ofillustration. These examples are provided in FIGS. 3 and 4 and relategenerally to a positive working diazo system and a positive workingphotocopying system, respectively. These examples are provided forpurposes of illustration only and are not meant to be limiting in anyfashion on the scope or application of the developer roll of thisinvention.

Referring now to FIG. 3 a diazo apparatus 20 is illustrated. The diazoapparatus 20 includes a light source 21 which is positioned to emitlight through an original 22 onto a reactive copy sheet 23. The original22 and reactive copy sheet 23 are then conveyed in abutting relationshipthrough driven roller 24 and guide roller 25. A separating apparatus 26then separates original 22 from copy 23.

The copy substrate 23 and more particularly the coated surface ofsubstrate 23 is then conveyed around developer or burnishing roller 27.Roller 27 consists of a driven mandrel 11 which is driven by motor 28.Burnishing roller 27 also includes flexible bristles 13. The surface 31of roller 27 is operated at a speed substantially faster than the speedof the copy paper 23. This provides the burnishing and developing effectwhich is desired to formulate the color between the co-reacted materialson the reactive surface of copy sheet 23. Copy sheet 23 is then advancedthrough driven roller 32 and guide roller 33. It should be noted thatrollers 25 and 33 do not exert rupturing pressure on the copy sheet.After exiting from rollers 32 and 33, the color and/or image will havebeen developed or will be in the process of developing. At this point intime, if a continuous roll is being used appropriate cutting orsectioning apparatus can be used to section the roll into sheets. Or, onthe other hand, if sheets of the particular substrate are being fedthrough the apparatus then the sheets can be ejected into appropriatecatching apparatus.

Although it has been shown to be essential that the surface speed of theroller be greater than the speed of the paper web or substrate theprecise ratio of roller speed to copy paper speed is not critical solong as the desired burnishing effect is achieved. In general, it isfelt that a ratio of roller speed to substrate speed of from about 10:1to about 500:1 is an effective range although a more preferred rangewould be 10:1 to 100:1 and a most preferred range would be 10:1 to 25:1.It is necessary to achieve a proper balance between speed of the rollerto produce the desired reaction and at the same time not cause damage tothe substrate.

The variety of combinations of imaging apparatus, light sources, rollerdrive mechanisms, motors to drive the developer roll, catchers or otherfinishing apparatus are infinite. The essential portion of thisinvention is the use of a developer roll such as has been described todevelop co-reactive materials without the necessity for the standardpressure rolls, pressure nips and the pertinent problems associatedtherewith.

Turning now to FIG. 4 a different piece of apparatus is shown forimaging and developing reactive copy sheets. In FIG. 4 what is referredto as a desk top copier is shown. In this embodiment, an original 40 isplaced with the written side 41 adjacent a glass or plastic,transparent, plate 42. A cover 43 is then lowered on top of the original40.

The copying process is initiated by actuation of switch 44 whichactivates light sources 45. Light sources 45 emit an appropriate light,such as ultraviolet, which is either selectively absorbed or reflectedoff of printed surface 41. The reflected light is then passed through anappropriately dimensioned lens 46 and then refocused on active surface47 of copy sheet 48. Copy sheet 48 can be either in sheet form or inroll form. The roll form is illustrated by number 50 in FIG. 4.

After a predetermined exposure time of active surface 47, the lightemitting sources 45 are turned off and the paper is advanced via rollers51 and 52, either or both of which may be driven, to a catching station53. Between rollers 51 and 52 is located developer or burnishing roller10 which is driven by drive motor or actuating means 54. Drive motor 54can be any of a variety of well-known electrical or mechanical motors.

Burnishing roller 10 is shown in its preferred embodiment which includesa mandrel 11 and a plurality of flexible bristles 13. In this fashionthe coating 47 is selectively exposed to actinic radiation emitted fromlight sources 45. In the preferred embodiment the microcapsules are thenselectively activated or deactivated whereupon burnishing by developerroller 10 a color is developed.

FIG. 5 illustrates one embodiment of the imaging system/copy paper whichis useful in combination with the developer roll of the presentinvention. In this copy paper a self-contained imaging sheet 60 isshown. The imaging sheet 60 is constituted by a substrate 62 coated witha layer of microcapsules 64. The microcapsules are filled with aninternal phase 66 containing a chromogenic material and a photosensitivesystem. Interposed between a layer of microcapsules 64 and the substrate62 is a layer of a developer material 70. In actuality, themicrocapsules 64 are not visible to the unaided eye.

Exposure of the imaging sheet 60 by transmission imaging is shown inFIG. 6 wherein a source of radiant energy 62 is positioned above thesurface of the imaging sheet 60 with a mask 74 therebetween. In thisillustration the photosensitive material is designated a resin curablematerial and, hence, the imaging sheet is positive working. Exposure isshown as solidifying the internal phase 66 in the exposed area 76whereas the internal phase 66 remains liquid in the unexposed areas 78.Transmission imaging has been selected to illustrate the inventionsystems operation for the ease with which it can be illustrated. Anequally common exposure means is reflection imaging which is used incopying printed documents.

FIG. 7 illustrates the imaging sheet 60 after the microcapsules havebeen ruptured. For simplification, the microcapsules are shown as beingruptured in the unexposed area 78 and unruptured in the exposed area 76.In actuality all or a portion of the capsules may also be ruptured inarea 76. In unexposed area 78 the chromogenic material and the developerreact to form a visible image 80. FIGS. 5, 6 and 7 represent but oneembodiment of the color producing substrate which is useful incombination with the developer roll of this invention.

Although several embodiments have been illustrated it should beunderstood that on many other commercially useful embodiments arecontemplated as coming within the scope of this invention. In one suchembodiment a plurality of developer rollers would be used instead of thesingle roller illustrated by the drawing. In another embodiment heatmeans would be supplied to act in combination with the developer roll.The heat supplied by this separate heat means would be in addition tothe heat which is typically produced as a by-product of the frictionbetween the developer roller and the reactive substrate.

While the invention has been illustrated and described in detail in thedrawings in the foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly the preferred embodiment has been shown and described and that allchanges and modifications that come within the spirit of the inventionare desired to be protected.

What is claimed is:
 1. Image-developing apparatus for use in combinationwith a color-producing substrate; said substrate including a coatingcomposition which contains a chromogenic material and a developermaterial, said chromogenic material being isolated from said developermaterial in said chromogenic material and said developer material beingco-reactive with said chromogenic material to form a color; said imagedeveloping apparatus comprising:(a) means for image-wise exposing saidcolor producing substrate; (b) means for advancing said exposedsubstrate to the developing section of said image-developing apparatus;(c) a developer roll for releasing said isolated chromogenic material,in the absense of rupturing pressure, by burnishing the surface of saidsubstrate; and (d) drive means for actuating said developer roll.
 2. Theimage developing apparatus of claim 1 wherein said developer rollincludes a fibrous outer surface and, wherein upon actuation by saiddrive means, said fibrous outer surface provides the force necessary torelease the isolated chromogenic material.
 3. The image developingapparatus of claim 2 wherein said fibrous outer surface comprises aplurality of flexible bristles.
 4. The image developing apparatus ofclaim 2 wherein said fibrous outer surface is felt.
 5. The imagedeveloping apparatus of claim 1 wherein a plurality of developer rollsare used to release said isolated chromogenic material.
 6. The imagedeveloping apparatus of claim 1 additionally comprising heat means foruse in combination with said developer roll to produce a color uponreaction of said chromogenic material with said developer material. 7.Image-developing apparatus for use in combination with a photosensitivesubstrate; said photosensitive substrate including a coating compositioncontaining an encapsulated chromogenic material, a photosensitivecomposition and a developer material, said developer material beingco-reactive with said chromogenic material to form a color; said imagedeveloping apparatus comprising:(a) means for image-wise exposing saidphotosensitive substrate; (b) means for advancing said exposedphotosensitive substrate to the developer section of saidimage-developing apparatus; (c) a developer roll for releasing saidencapsulated chromogenic material, in the absence of rupturing pressure,by burnishing the surface of said photosensitive substrate; and (d)drive means for actuating said developer roll.
 8. The image developingapparatus of claim 1 wherein said developer roll includes a fibrousouter surface, said fibrous outer surface, upon actuation by said drivemeans, providing the force necessary to rupture the microcapsulescontaining said chromogenic material.
 9. The image developing apparatusof claim 8 wherein said fibrous outer surface comprises a plurality offlexible bristles.
 10. The image developing apparatus of claim 8 whereinsaid fibrous outer surface is felt.
 11. The image developing apparatusof claim 7 wherein a plurality of developer rolls are used to releasesaid encapsulated chromogenic material.
 12. The image developingapparatus of claim 7 additionally comprising heat means for use incombination with said developer roll to produce a color upon reaction ofsaid chromogenic material with said developer material. 13.Image-developing apparatus for use in combination with a photosensitivesubstrate; said photosensitive substrate including a coating compositioncontaining microcapsules, said microcapsules containing a solution of achromogenic material and a photosensitive composition, and a colordeveloper material, said color developer material being co-reactive withsaid chromogenic material; said image developing apparatuscomprising:(a) means for image-wise exposing said photosensitivesubstrate; (b) drive means for advancing said exposed photosensitivesubstrate to said image developing apparatus; (c) a developer roll forreleasing said encapsulated material in the absence of rupturingpressure by burnishing the surface of said exposed photosensitivesubstrate, said developer roll including a fibrous outer surface, saidfibrous outer surface, when rotated, providing the force necessary torupture said microcapsules; and (d) drive means for actuating saiddeveloper roll.
 14. The image developing apparatus of claim 13 whereinsaid fibrous outer surface comprises a plurality of flexible bristles.15. The image developing apparatus of claim 13 wherein said fibrousouter surface is felt.